Preparation method of hollow graphene@IVA group oxide composite material and its products and applications

Abstract

The present invention discloses a method for preparing a hollow graphene@Group IVA oxide composite material, comprising the following steps: S1: mixing a template and phthalocyanine; S2: pyrolyzing the material obtained in step S1 at high temperature, followed by cooling to room temperature; S3: adding an alcohol solvent and a surfactant to the material obtained in step S2, mixing them uniformly, then adding a carbon group element source and stirring, and then adding water for hydrolysis, washing the reaction product with an organic solvent and drying to obtain a composite powder; S4: pyrolyzing the composite powder in step S3, followed by washing and drying to obtain the hollow graphene@Group IVA oxide composite material. The composite material can be used to prepare a porous negative electrode material for lithium-ion batteries, exhibiting good electrochemical performance in a half-cell and effectively mitigating the volume expansion of tin dioxide and silicon oxide during charge and discharge.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a preparation method of a hollow graphene@IVA group oxide composite material, and its products and applications. Background Art

[0002] With the rapid development of electric vehicles, the next generation of lithium-ion batteries urgently needs to be safe and clean energy storage systems with higher energy storage capacity and power output.

[0003] Tin and silicon in the IVA group, and their derivatives (such as tin-based alloys, tin oxides / sulfides, silicon, silicon dioxide, and silicon-carbon materials), have garnered significant attention due to their high theoretical capacities. For example, SnO2 has a theoretical capacity of 1494 mAh / g, elemental silicon can reach 4200 mAh / g, and silicon oxide has 1965 mAh / g. However, IVA materials can experience volume changes of up to 300% during cycling, and the active materials are prone to agglomeration, resulting in rapid capacity decay.

[0004] Graphene is generally considered to be an ideal composite matrix for SnO2 due to its large specific surface area, high electrical conductivity and good flexibility. However, SnO2 particles on the surface of graphene (rGO) sheets tend to agglomerate and fall off during electrochemical cycling, causing the cycling performance of SnO2@graphene composite materials to rapidly decay. Cubic graphene is a stable structure that usually exhibits excellent electrochemical performance in energy storage devices such as batteries due to its effective ion transport channels and relatively stable framework. However, traditional carbon materials have a low lithium plating potential and are prone to the formation of lithium dendrites, which endangers the safety of lithium-ion batteries. Therefore, there is an urgent need to compositely modify carbon materials to obtain a safer electrode material with higher energy storage capacity and power output. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies of the prior art and to provide a method for preparing a hollow graphene@IVA group oxide composite material, a product thereof and its application as a porous negative electrode for lithium-ion batteries, so as to at least achieve the effect of improving the cycle stability and specific capacity of the battery.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a hollow graphene@IVA group oxide composite material, characterized by comprising the following steps:

[0008] S1: Mix the template and phthalocyanine (CAS No.: 574-93-6);

[0009] S2: The material obtained in step S1 is subjected to high-temperature cracking and then cooled to room temperature;

[0010] S3: adding an alcohol solvent and a surfactant to the material obtained in step S2 and mixing them evenly, then adding a carbon group element source and stirring, and then adding water to carry out a hydrolysis reaction. The reaction product is washed with an organic solvent and then dried to obtain a composite powder;

[0011] The stirring time is 30-40 minutes, and the hydrolysis reaction time is 12-96 hours. The hydrolysis reaction is carried out at room temperature with continuous stirring during the reaction.

[0012] S4: subjecting the composite powder described in step S3 to high temperature treatment, and then washing and drying to obtain a hollow graphene@IVA group oxide composite material.

[0013] Furthermore, the template is a salt crystal with a melting point of 500° C. (the decomposition temperature of phthalocyanine is about 500° C.) or above. Preferably, the template includes sodium chloride crystals, potassium chloride crystals or magnesium chloride crystals.

[0014] Furthermore, the particle size of the salt crystals is 1 μm to 30 μm.

[0015] Furthermore, in step S1, the template agent is 5-20 parts, and the phthalocyanine is 0.01-2 parts by weight.

[0016] Furthermore, in step S2, the specific method of the high temperature cracking is: heating from room temperature to 300-400°C at a heating rate of 5°C / min, then heating to 600-1200°C at a heating rate of 2°C / min and maintaining for 0.5-36h.

[0017] Preferably, the specific method of the high-temperature pyrolysis is: heating from room temperature to 350°C at a heating rate of 5°C / min, then heating to 700°C at a heating rate of 2°C / min and maintaining for 8 hours.

[0018] Furthermore, in step S3, by weight, the material obtained in step S2 is 1-2 parts, the alcohol solvent is 150 parts, the surfactant is 0.1-0.2 parts, the carbon group element source is 1-10 parts, and the water is 0.1-10 parts.

[0019] Preferably, the alcohol solvent is ethanol.

[0020] The surfactant includes hexadecylamine, n-tetradecylamine, and Tween. Preferably, the surfactant is hexadecylamine.

[0021] Furthermore, in step S3, the organic solvent includes ethanol, toluene, hexane, acetone, and carbon tetrachloride. Preferably, the organic solvent is ethanol.

[0022] Furthermore, in step S3, the carbon group element source includes a tin source, a silicon source and a titanium source; preferably a tin source and a silicon source.

[0023] The tin source includes at least one of stannous isooctanoate, tin tetrachloride, organic tin alcohol, tin iodide, tin tetrachloride pentahydrate, tin acetate and stannous chloride; preferably, the tin source is stannous isooctanoate.

[0024] The silicon source includes at least one of tetraethyl silicate, vinyltriethoxysilane and trimethylchlorosilane; preferably, the silicon source is tetraethyl silicate.

[0025] The titanium source includes tetrabutyl titanate and isopropyl titanate.

[0026] Furthermore, when the carbon group element is a tin source, in step S4, the high temperature treatment method is: reacting the composite powder in an inert gas at 300-1200° C. for 0.5-35 hours.

[0027] Preferably, the high temperature treatment method is: reacting the composite powder in an inert gas at 450° C. for 2 hours.

[0028] Furthermore, when the carbon group element is a silicon source, in step S4, the method of high temperature treatment is: by weight, add 10 to 20 parts of thermal conductor, 1 to 2 parts of metal magnesium powder and 0.1 to 2 parts of silicon powder to 1 part of the composite powder, and react in an inert gas at 500-1200°C for 0.5-12 hours.

[0029] Preferably, the high temperature treatment method is: by weight, add 10 to 20 parts of thermal conductor, 1 to 2 parts of metal magnesium powder and 0.1 to 2 parts of silicon powder to 1 part of the composite powder, and react in an inert gas at 1000°C for 3 hours.

[0030] A second object of the present invention is to provide a hollow graphene@IVA group oxide composite material prepared by the preparation method.

[0031] The third object of the present invention is to provide an application of the hollow graphene@IVA group oxide composite material for preparing a porous negative electrode material for lithium-ion batteries.

[0032] The beneficial effects of the present invention are:

[0033] 1. The process and raw materials involved in preparing cubic graphene using CVD-like methods are simple, making it easy to produce on a large scale.

[0034] 2. The hydrolysis and pyrolysis processes are also very simple. The hollow structure of cubic graphene effectively mitigates the volume expansion of tin dioxide and silicon oxide during charge and discharge. Also noteworthy is the potential for constructing porous electrodes using this hollow structure, thereby improving lithium-ion transport efficiency and enabling the composite material to exhibit excellent electrochemical performance in a half-cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The SEM and element distribution images of the tin dioxide-coated hollow cubic graphene prepared in Example 1;

[0036] Figure 2 is a SEM image of the silicon dioxide-coated hollow cubic graphene prepared in Example 2;

[0037] Figure 3 The CV curves obtained from cyclic voltammetry tests of the tin dioxide-coated hollow cubic graphene prepared in Example 1 and its comparison sample, pure silicon dioxide (test voltage range 0.01-3.0 V, test voltage sweep rate 1 mV / s, test number of cycles 3).

[0038] Figure 4 The electrochemical impedance spectroscopy (EIS) of the tin dioxide-coated hollow cubic graphene prepared in Example 1 and its comparative sample, pure tin dioxide;

[0039] Figure 5 The cyclic performance of the tin dioxide-coated hollow cubic graphene prepared in Example 1 and its comparative sample pure tin dioxide under high rate (2 A / g) charge and discharge. DETAILED DESCRIPTION

[0040] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0041] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0042] Unless otherwise specified, the reagents and materials used in the following examples can be obtained from commercial sources.

[0043] The electrode sheet is made by physically mixing the active material with a conductive agent (Super P) and a binder (poly(vinylidene boron difluoride)) in a weight ratio of 8:1:1 using N-methyl-2-pyrrolidone (NMP) as a solvent. The slurry is then evenly coated on copper foil and vacuum-dried at 70 degrees for 12 hours. A Celgard 2500 membrane is used as the battery separator, and 1M LiPF6 is used as the electrolyte (ethylene carbonate: diethyl carbonate = 1:1, volume ratio). The cells are assembled with lithium sheets into CR2032 button-type half-cells in a glove box.

[0044] Electrochemical impedance spectroscopy and cyclic voltammetry were performed using a Chenhua CH760E electrochemical workstation. Charge and discharge curves were measured in the voltage range of 0.01V to 3.0V using a Blue Power CT2001A battery system.

[0045] Example 1

[0046] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0047] Step (1): preparing potassium chloride crystals with a particle size of 1 μm to 30 μm using an anti-solvent method.

[0048] Step (2): Physically mix 14 parts of potassium chloride crystals with 0.1 parts of metal-free phthalocyanine.

[0049] Step (3): The mixture obtained in step (2) is subjected to a high-temperature cracking treatment. The reaction temperature treatment program is as follows: heating from room temperature to 350°C at a heating rate of 5°C / min, then heating to 700°C at a heating rate of 2°C / min and holding for 8 hours, and finally cooling naturally. The product is labeled as SALT-Gr.

[0050] Step (4): Weigh 1 gram of SALT-Gr from step (3), add 150 milliliters of ethanol, sonicate, then add 0.1 gram of hexadecylamine and stir for 10 minutes. Then, add 1 milliliter of stannous isooctanoate and stir for 30 minutes. Then, slowly add 1 milliliter of water dropwise. Finally, stir at room temperature for 24 hours and wash with ethanol to obtain tin hydroxide-coated SALT-Gr.

[0051] Step (5): The sample obtained in step (4) was pyrolyzed to obtain tin dioxide-coated SALT-Gr. The pyrolysis procedure was 450°C argon treatment for two hours. Finally, the salt was washed away with deionized water to obtain a hollow core-shell structure SnO2@graphene composite (see Figure 1 ),from Figure 1 It can be seen that tin dioxide is evenly coated on the surface of the cube with a side length of 20 to 25 μm.

[0052] The production process of the SnO2@graphene composite negative electrode sheet is as follows: the active material and the conductive agent (SuperP) and the adhesive poly(propylene boron difluoride) (PVDF) are physically mixed, and N-methyl-2-pyrrolidone (NMP) is used as a solvent, and the mixing weight ratio is 8:1:1. The slurry is then evenly coated on the copper foil and vacuum dried at 70 degrees for 12 hours. Celgard2500 membrane is used as a battery separator, 1M LiPF6 is used as an electrolyte (ethylene carbonate: diethyl carbonate = 1:1, volume ratio), and a CR2032 button half-cell is assembled with a lithium sheet in a glove box. Electrochemical impedance and cyclic voltammetry tests were performed using Chenhua electrochemical workstation CH760E. The electrochemical AC impedance value of the tin dioxide@graphene composite was measured to be 48Ω (see Appendix Figure 4 ), the cyclic voltammogram of SnO2@graphene is shown in the attached figure. Figure 3 shown.

[0053] The charge and discharge curves were measured using a Blue Power CT2001A battery system within a voltage range of 0.01V to 3.0V. At 2A / g, the discharge capacity of the first cycle of high-rate charge and discharge was 2307.4mAh / g, and after 200 cycles, it was 450.0mAh / g (see attached). Figure 5 ).

[0054] Example 2

[0055] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0056] Step (1): preparing sodium chloride crystals with a particle size of 1 μm to 30 μm using an anti-solvent method.

[0057] Step (2): 14 parts of sodium chloride crystals are physically mixed with 0.1 parts of metal-free phthalocyanine.

[0058] Step (3): The mixture obtained in step (2) is subjected to a high-temperature cracking treatment. The reaction temperature treatment program is as follows: heating from room temperature to 350°C at a heating rate of 5°C / min, then heating to 700°C at a heating rate of 2°C / min and holding for 8 hours, and finally cooling naturally. The product is labeled as SALT-Gr.

[0059] Step (4): Weigh 1 gram of SALT-Gr from step (3), add 150 milliliters of ethanol, sonicate, then add 0.1 gram of hexadecylamine and stir for 10 minutes. Then, add 1 milliliter of stannous isooctanoate and stir for 30 minutes. Then, slowly add 1 milliliter of water dropwise. Finally, stir at room temperature for 24 hours and wash with ethanol to obtain tin hydroxide-coated SALT-Gr.

[0060] Step (5): The sample obtained in step (4) was pyrolyzed to obtain tin dioxide-coated SALT-Gr. The pyrolysis procedure was 450°C in argon for two hours. Finally, the salt was washed away with deionized water to obtain a hollow core-shell structured SnO2@graphene composite.

[0061] Example 3

[0062] A porous negative electrode material for a lithium-ion battery was prepared using the same method as in Example 1, except that step (2) was modified to physically mix one part of potassium chloride crystals with one part of metal-free phthalocyanine. The remaining steps were the same as in Example 1, yielding graphene-SnO2 composites of varying thicknesses.

[0063] Example 4

[0064] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0065] Step (1): preparing potassium chloride crystals with a particle size of 1 μm to 30 μm using an anti-solvent method.

[0066] Step (2): Physically mix 14 parts of potassium chloride crystals with 0.1 parts of metal-free phthalocyanine.

[0067] Step (3): The mixture obtained in step (2) is subjected to a high-temperature cracking treatment. The reaction temperature treatment program is as follows: heating from room temperature to 350°C at a heating rate of 5°C / min, then heating to 700°C at a heating rate of 2°C / min and holding for 8 hours, and finally cooling naturally. The product is labeled as SALT-Gr.

[0068] Step (4): Weigh 1 gram of SALT-Gr from step (3), add 150 milliliters of ethanol, sonicate, then add 0.1 gram of hexadecylamine and stir for 10 minutes. Then, add 1 milliliter of tetraethyl silicate and stir for 30 minutes. Then, slowly add 1 milliliter of water dropwise. Finally, stir at room temperature for 24 hours, wash with ethanol, and dry.

[0069] Step (5): Take 2g of the sample obtained in step (4), add 2g of sodium chloride as a thermal conductor, add 2g of metal magnesium powder and 0.12g of silicon powder, and finally treat it in argon at 1000℃ for three hours. Finally, use deionized water to wash away the salt to obtain a hollow graphene@SiOx composite (see Figure 2 ). Figure 2 It can be seen that the overall cubic structure is retained after removing the template, and the side length of the cube is 4 to 5 μm. This hollow cubic structure with a certain rigidity can be used to effectively construct a porous graphene@SiOx electrode.

[0070] Example 5

[0071] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0072] Step (1): preparing potassium chloride crystals with a particle size of 1 μm to 30 μm using an anti-solvent method.

[0073] Step (2): Physically mix 1 part of potassium chloride crystals with 1 part of metal-free phthalocyanine.

[0074] Step (3): The mixture obtained in step 2 is subjected to a high-temperature cracking treatment. The reaction temperature treatment program is as follows: heating from room temperature to 350°C at a heating rate of 5°C / min, then heating to 700°C at a heating rate of 2°C / min and holding for 8 hours, and finally cooling naturally. The product is labeled as SALT-Gr.

[0075] Step (4): Weigh 1 gram of SALT-Gr from step 3, add 150 milliliters of ethanol, sonicate, then add 0.1 gram of hexadecylamine and stir for 10 minutes. Then, add 1 milliliter of tetraethyl silicate and stir for 30 minutes. Then, slowly add 1 milliliter of water dropwise. Finally, stir at room temperature for 24 hours, wash with ethanol, and dry.

[0076] Step (5): Take 2 g of the sample obtained in step 4, add 2 g of sodium chloride as a thermal conductor, 2 g of magnesium powder, and 0.12 g of silicon powder, and finally treat at 1000°C in argon for three hours. Finally, wash away the salt with deionized water to obtain a hollow graphene@SiOx composite.

[0077] Comparative Example 1

[0078] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0079] Add 0.1 g of hexadecylamine to 150 ml of ethanol and stir for 10 minutes. Then add 1 ml of stannous isooctanoate and stir for 30 minutes. Then slowly add 1 ml of water dropwise. Finally, stir at room temperature for 24 hours and wash with ethanol to obtain tin hydroxide. Treat with argon at 450°C for two hours to remove the organic solvent and decompose the tin hydroxide into white SnO2 particles.

[0080] Comparative Example 2

[0081] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0082] One gram of graphene oxide powder was weighed and added to 150 milliliters of ethanol and ultrasonically dispersed for 30 minutes. Then, 0.1 gram of hexadecylamine was added and stirred for 10 minutes. One milliliter of stannous isooctanoate was added and stirred for 30 minutes. One milliliter of water was slowly added dropwise. Finally, the mixture was stirred at room temperature for 24 hours and washed with ethanol to obtain a tin hydroxide-graphene oxide composite. The resulting mixture was filtered and dried in an 80-degree Celsius oven for 24 hours to obtain a powder sample.

[0083] The obtained powder sample was heat treated at 800°C under argon conditions for two hours to obtain a SnO2@graphene composite.

[0084] Comparative Example 3

[0085] A porous negative electrode material for a lithium-ion battery is prepared by the following method:

[0086] Add 0.1 g of hexadecylamine to 150 ml of ethanol and stir for 10 minutes. Then add 1 ml of tetraethyl silicate and stir for 30 minutes. Then slowly add 1 ml of water dropwise. Finally, stir at room temperature for 24 hours to obtain a nano-scale hydrolyzed product. Wash with anhydrous ethanol and then dry at 80°C for 24 hours.

[0087] Take 2 g of the sample from the previous step, add 2 g of metallic magnesium powder and 0.12 g of silicon powder, and then heat treat it in an argon atmosphere at 1000°C for 3 hours to obtain SiOx white particles.

[0088] Experimental example

[0089] The composite materials of Examples 2-6 and Comparative Examples 1-3 were used as negative electrode active materials for lithium-ion batteries. They were individually assembled with lithium sheets in a glove box according to the method of Example 1 to form CR2032 button-type half-cells. Electrochemical performance was analyzed using a Chenhua CH760E electrochemical workstation and a Blue Power CT2001A battery system. The results are summarized in Table 1, including electrochemical impedance spectroscopy (ECI), discharge capacity at the first high-rate charge / discharge cycle at 2 A / g, and capacity after 200 cycles.

[0090] Table 1

[0091]

[0092]

[0093] As can be seen from Table 1, when comparing Example 1 and Example 2, using potassium chloride crystals as a thermal conductor and template has better electrochemical performance than sodium chloride crystals; when comparing Example 1 and Example 3, the larger the ratio of potassium chloride crystals to metal-free phthalocyanine, the smaller the thickness of the prepared graphene, and the better the electrochemical performance of the corresponding lithium-ion battery, that is, the electrochemical performance of Example 1 is better than that of Example 3; and when comparing Example 1 and Example 4, among the composites of Group IVA oxides and graphene, the graphene@SnO2 composite material has better electrochemical performance than the graphene@SiOX composite, especially in terms of improving the lithium ion migration rate and curbing the volume expansion of the electrode material, the graphene@SnO2 composite (Example 1) is better.

[0094] Attachment Figure 3This is the CV curve of the graphene@SnO2 composite material of Example 1 and the comparative sample (Comparative Example 1) pure tin dioxide after being assembled into a CR2032 battery. The voltage sweep rate is 1mV / s, and the test voltage range is 0.01~3.0V (relative to Li / Li+). The cathode peak at 0.7 volts in the first cycle disappears after the second cycle, corresponding to the non-decomposability of tin dioxide. At the same time, the curve area decreases, corresponding to the formation of an irreversible solid electrolyte interface (SEI). The two anode peaks of 0.5V and 1.2V and the three cathode peaks of 0.01V, 0.16V, and 1.0V correspond to the insertion and deinsertion process of lithium ions. At the same time, it can be seen that the CV integral area of graphene@SnO2 is much larger than that of pure tin dioxide material. It can be inferred that the graphene@SnO2 composite material has a larger specific capacity than the pure tin dioxide material. Figure 4 This graph shows the electrochemical impedance of the graphene@SnO2 composite material described in Example 1 and pure SnO2 (Comparative Example 1) after assembly into a CR2032 battery. A comparison shows that the charge transfer impedance of the hollow SnO2-graphene composite material is much lower than that of pure SnO2 in the high-frequency range. Meanwhile, the slope of the graphene@SnO2 composite material is much higher than that of pure SnO2 in the low-frequency range, indicating rapid lithium ion conduction. Figure 5 Figure 1 shows the long-term cycling performance of the graphene@SnO2 composite material from Example 1 and the comparative SnO2 sample (Comparative Example 1) at high current density. Due to irreversible capacity, the capacity decreases after the first cycle, remaining around 500 mAh / g. It can be seen that the performance of graphene@SnO2 outperforms pure tin dioxide in both initial discharge capacity and capacity after 200 cycles (450 mAh / g).

[0095] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A method for preparing a hollow graphene@IVA group oxide composite material, characterized in that: The following steps are involved: S1: mixing the template and phthalocyanine; S2: The material obtained in step S1 is subjected to high-temperature cracking and then cooled to room temperature; S3: adding an alcohol solvent and a surfactant to the material obtained in step S2 and mixing them evenly, then adding a carbon group element source and stirring, and then adding water to carry out a hydrolysis reaction. The reaction product is washed with an organic solvent and then dried to obtain a composite powder; S4: subjecting the composite powder described in step S3 to high temperature treatment, and then washing and drying to obtain a hollow graphene@IVA group oxide composite material; Wherein, in step S3, the carbon group element source is a tin source or a silicon source; The tin source comprises at least one of stannous isooctanoate, tin tetrachloride, organic tin alcohol, tin iodide, tin tetrachloride pentahydrate, tin acetate and stannous chloride; The silicon source includes at least one of tetraethyl silicate, vinyltriethoxysilane and trimethylchlorosilane; The template is at least one of sodium chloride crystals, potassium chloride crystals or magnesium chloride crystals, wherein the particle size of the salt crystals is 1 μm to 30 μm; In step S3, by weight, the material obtained in step S2 is 1-2 parts, the alcohol solvent is 150 parts, the surfactant is 0.1-0.2 parts, the carbon group element source is 1-10 parts, and the water is 0.1-10 parts; In step S2, the specific method of the high temperature cracking is: heating from room temperature to 300-400°C at a heating rate of 5°C / min, then heating to 600-1200°C at a heating rate of 2°C / min and maintaining for 0.5-36h.

2. The preparation method according to claim 1, wherein: In step S1, the template agent is 5-20 parts by weight, and the phthalocyanine is 0.01-2 parts by weight.

3. The preparation method according to claim 1, wherein: When the carbon group element is a tin source, in step S4, the high temperature treatment method is: reacting the composite powder in an inert gas at 300-1200° C. for 0.5-36 hours.

4. The preparation method according to claim 1, wherein: When the carbon group element is a silicon source, in step S4, the method of the high-temperature treatment is: by weight, add 10-20 parts of a thermal conductor, 1-2 parts of metal magnesium powder and 0.1-2 parts of silicon powder to 1 part of the composite powder, and react in an inert gas at 500-1200°C for 0.5-12 hours.

5. A hollow graphene@IVA group oxide composite material prepared by the preparation method according to claims 1-4.

6. The use of the hollow graphene@IVA group oxide composite material according to claim 5, characterized in that: Used as a porous negative electrode material for preparing lithium-ion batteries.

Images